Add consistency check that mutates the AST and checks if pattern matching finds the difference.

ICSharpCode.NRefactory.CSharp/Ast/SyntaxTree.cs

@@ -132,7 +132,7 @@ namespace ICSharpCode.NRefactory.CSharp
 		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
 		{
 			SyntaxTree o = other as SyntaxTree;
-			return o != null && GetChildrenByRole(MemberRole).DoMatch(o.GetChildrenByRole(MemberRole), match);
+			return o != null && this.Members.DoMatch(o.Members, match);
 		}
 		
 		public override void AcceptVisitor (IAstVisitor visitor)

ICSharpCode.NRefactory.ConsistencyCheck/CSharpFile.cs

@@ -50,6 +50,7 @@ namespace ICSharpCode.NRefactory.ConsistencyCheck
 			// Keep the original text around; we might use it for a refactoring later
 			this.OriginalText = File.ReadAllText(fileName);
 			this.SyntaxTree = p.Parse(this.OriginalText, fileName);
+			this.SyntaxTree.Freeze(); // the various tests shouldn't modify the AST shared by all tests
 			
 			if (p.HasErrors) {
 				Console.WriteLine("Error parsing " + fileName + ":");

ICSharpCode.NRefactory.ConsistencyCheck/ICSharpCode.NRefactory.ConsistencyCheck.csproj

@@ -74,6 +74,7 @@
     <Compile Include="CSharpFile.cs" />
     <Compile Include="CSharpProject.cs" />
     <Compile Include="FindReferencesConsistencyCheck.cs" />
+    <Compile Include="PatternMatchingTest.cs" />
     <Compile Include="TypeSystemTests.cs" />
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />

ICSharpCode.NRefactory.ConsistencyCheck/Program.cs

@@ -66,6 +66,7 @@ namespace ICSharpCode.NRefactory.ConsistencyCheck
 			RunTestOnAllFiles("Resolver test (no parsed file)", ResolverTest.RunTestWithoutUnresolvedFile);
 			RunTestOnAllFiles("Resolver test (randomized order)", RandomizedOrderResolverTest.RunTest);
 			new FindReferencesConsistencyCheck(solution).Run();
+			RunTestOnAllFiles("Pattern Matching test", PatternMatchingTest.RunTest);
 			
 			Console.Write("Press any key to continue . . . ");
 			Console.ReadKey(true);